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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

STMicroelectronics BUY69A

Name: BUY69A
Brand: STMicroelectronics
SKU: BUY69A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BUY69A

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-204AA, TO-3

Datasheet:: BUY69A.pdf

Description:: TRANS NPN 400V 10A TO-3

Quantity:: RFQ Add To RFQ list

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Inventory:4,774

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Product details

Overview

BUY69A from STMicroelectronics is a high-voltage, high-current NPN silicon transistor in a TO-3 metal package, designed for horizontal deflection output stages in color TV receivers and fast-switching industrial power applications. It delivers 1000 V V_CES, 10 A continuous collector current, 100 W total dissipation at T_c ≤ 25 °C, and sub-microsecond switching (t_on = 0.2 µs, t_s = 1.7 µs).

For engineers reviewing the BUY69A datasheet, BUY69A pinout, BUY69A application, or BUY69A equivalent, key selection criteria include sustained 400 V V_CEO(sus) at 100 mA, 3.3 V V_CE(sat) at 8 A/2.5 A drive, 15 minimum h_FE at 2.5 A, and thermal resistance of 1.75 °C/W junction-to-case - critical for high-reliability deflection and regulator designs.

Technical Context

The BUY69A employs a multi-epitaxial mesa structure to achieve high breakdown voltage and rugged second-breakdown performance. Its design supports non-repetitive 4 A I_s/b at V_CE = 25 V and fast transition frequency (f_T = 10 MHz), enabling stable operation under high-dV/dt and high-di/dt conditions typical in flyback and line-output circuits.

It operates with a maximum junction temperature of 200 °C and storage range from –65 °C to +200 °C, validated for use in thermally demanding horizontal deflection yoke drivers and switching regulator primary-side switches where thermal cycling and voltage transients are severe.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CES	1000 V - Withstands full-line surge and flyback spikes in CRT horizontal deflection without avalanche conduction.
V_CEO(sus)	400 V at I_C = 100 mA - Sustains rated voltage during active switching in regulated power supplies.
I_C	10 A continuous - Supports high-power yoke current drive and primary-side switching in >100 W converters.
V_CE(sat)	3.3 V at I_C = 8 A, I_B = 2.5 A - Limits conduction loss to ≤26.4 W, enabling efficient thermal management in TO-3.
t_on/t_s/t_f	0.2 / 1.7 / 0.3 µs - Enables clean, low-overshoot switching at line frequencies up to 16 kHz with minimal snubber demand.
R_thj-case	1.75 °C/W - Allows direct heatsink mounting to maintain T_j < 200 °C at 100 W dissipation with modest heatsinking.
h_FE	≥15 at I_C = 2.5 A, V_CE = 10 V - Ensures reliable base drive margin in saturated-switch applications with aging and temperature drift.

Pinout & Package

Package: TO-3 metal case (JEDIC standard), with collector electrically connected to the case. Dimensions per STMicroelectronics mechanical drawing: A = 11.0–13.1 mm, E = 19.0–20.0 mm, P = 25.0–26.0 mm, U = 38.5–39.3 mm.

Pin/Terminal	Circuit Role	Design Meaning
Case (Tab)	Collector (C)	Electrically active collector terminal; requires insulated mounting hardware when isolated collector bias is needed.
Lead 1	Base (B)	Control input; driven with ≥2.5 A peak for full saturation at 8 A I_C.
Lead 2	Emitter (E)	Power return path; low-inductance connection essential to minimize switching oscillation in deflection circuits.

Key Features

Feature	Design Value
Multi-epitaxial mesa construction	Enables simultaneous high V_CES (1000 V) and high I_C (10 A) without trade-off in ruggedness or SOA.
Second breakdown rating	4 A at V_CE = 25 V (1 s pulse) - prevents catastrophic failure during transient overloads in TV yoke circuits.
Fast switching timing	0.2 µs turn-on + 1.7 µs storage time - reduces switching losses and EMI generation in 15.625 kHz horizontal deflection.
High junction temperature rating	200 °C max operating temperature - supports operation in sealed, convection-limited TV chassis environments.
TO-3 metal package	Provides robust mechanical stability and superior thermal conduction vs. plastic packages for high-power analog switching.

Applications

Color TV Horizontal Deflection

Switching Regulator Primary Switch

Use Scenario: Driving CRT horizontal deflection yoke in 15.625 kHz line-scan circuits with flyback energy recovery.

IC Role / Device Role / Timing Role: High-voltage NPN switch handling 1000 V flyback spikes and 8–10 A peak yoke current.

Use Value: 1.75 °C/W R_thj-case and 200 °C T_jmax ensure reliability across ambient temperatures up to 70 °C in enclosed TV cabinets.

Use Scenario: Primary-side switching element in offline 50–200 W DC-DC converters using forward or flyback topology.

IC Role / Device Role / Timing Role: High-voltage, high-current power switch controlling transformer primary current with fast turn-off to limit core reset time.

Use Value: 400 V V_CEO(sus) and 10 MHz f_T support stable regulation under wide input voltage ranges and load transients.

Industrial AC Motor Starter

High-Voltage Capacitor Discharge Circuit

Use Scenario: Solid-state contactor for 3-phase motor starting, switching 400 VAC line-to-line with inductive kick suppression.

IC Role / Device Role / Timing Role: Rugged NPN switch absorbing inductive energy via external snubber while maintaining safe SOA.

Use Value: Second-breakdown rating (4 A @ 25 V) and 1000 V V_CES prevent latch-up during repetitive inductive turn-off events.

Use Scenario: Triggered discharge switch for flash lamps or pulsed laser diodes requiring precise 1–10 ms high-current pulses.

IC Role / Device Role / Timing Role: Fast-turning, high-peak-current switch discharging 100–1000 µF capacitors at up to 15 A peak.

Use Value: 15 A I_CM and 0.3 µs fall time enable sharp, repeatable pulse edges with minimal tail current.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BU2520DX	V_CES = 1500 V, I_C = 12 A, R_thj-case = 1.5 °C/W, TO-3P plastic package	Higher voltage margin but lower thermal conductivity; no metal case for direct heatsinking	Preferred where higher surge immunity is required and thermal interface can be optimized with thermal paste/pads.
2SC5200	V_CEO = 230 V, I_C = 15 A, f_T = 30 MHz, TO-3P	Lower voltage rating but higher gain and speed; unsuitable for 400+ V sustaining applications	Only viable in low-input-voltage (<200 VDC) switching regulators or audio output stages - not a drop-in replacement.

Compared with BU2520DX and 2SC5200, the BUY69A uniquely balances 1000 V capability, metal-case thermal performance, and proven CRT deflection ruggedness - making it irreplaceable in legacy high-voltage analog video systems and industrial flyback designs where SOA and thermal mass are decisive.

Availability

BUY69A is available at Aetrix Electronics and suitable for horizontal deflection circuits, switching regulators, and industrial motor control systems requiring stable component supply and long-term lifecycle continuity.

Supply support for BUY69A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, MCU, and sensor solutions for automotive, industrial, and consumer markets.

The BUY69A belongs to ST's high-voltage power transistor product line, engineered specifically for CRT television deflection and industrial switching applications demanding extreme voltage endurance and thermal resilience.

FAQ

Is BUY69A still in active production?

No - BUY69A is marked "Obsolete Product(s)" in the official STMicroelectronics datasheet (October 2003 revision). However, Aetrix Electronics maintains legacy inventory with full traceability and offers extended lifecycle support including cross-reference engineering and controlled-batch sourcing for ongoing production needs.

Can BUY69A be used as a direct replacement for BU2508AX?

No - BU2508AX has V_CES = 1500 V and different SOA characteristics. While both are TO-3 NPN transistors for deflection, BUY69A's lower V_CES and distinct second-breakdown profile require circuit-level validation, especially in snubber design and base drive strength.

What is the recommended base drive for saturation at 8 A collector current?

ST specifies 2.5 A peak base current (I_B) with 3.3 V V_CE(sat) at I_C = 8 A. A driver capable of delivering ≥3 A peak into ≤1 Ω source impedance is recommended to ensure full saturation across temperature and device variation.

Does BUY69A require a mica insulator when mounted to a heatsink?

Yes - because the metal case is electrically connected to the collector, electrical isolation from the heatsink is mandatory unless the heatsink is at collector potential. ST recommends a mica washer with silicone grease or a ceramic insulator meeting ≥2 kV dielectric strength and ≤0.2 °C·in²/W thermal resistance.

BUY69A Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-204AA, TO-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 10 A

Voltage - Collector Emitter Breakdown (Max):: 400 V

Vce Saturation (Max) @ Ib, Ic:: 3.3V @ 2.5A, 8A

Current - Collector Cutoff (Max):: 1mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 15 @ 2.5A, 10V

Power - Max:: 100 W

Frequency - Transition:: 10MHz

Operating Temperature:: 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Chassis Mount

Supplier Device Package:: TO-3

BUY69A FAQ

1.How can I place an order for BUY69A through Aetrix?

Please submit a Request for Quotation (RFQ) for BUY69A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BUY69A reliable?

The price and inventory of BUY69A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BUY69A is usually 5 days.

3.What payment methods are accepted for BUY69A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BUY69A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BUY69A?

BUY69A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BUY69A order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BUY69A?

For technical support, including BUY69A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BUY69A requirements.

6.How does Aetrix verify that BUY69A is sourced from the original manufacturer or authorized distributors?

All BUY69A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BUY69A meets industry standards.

7.What is the process for return or replacement of BUY69A?

All BUY69A units undergo pre-shipment inspection (PSI). If there is an issue with BUY69A, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BUY69A part is unused and in its original packaging.

Return procedure for BUY69A:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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